The present invention relates to a high-frequency power amplifier device, and more particularly to an effective technology applicable to a high-frequency power amplifier device that, in accordance with an output level setting for transmission, changes the transistor to be used.
In a configuration described, for instance, in U.S. Pat. No. 7,135,919, a first amplifier and a second amplifier are coupled to a common output node. The first and second amplifiers are complementarily activated. A transmission line having a length of λ/4 is provided between the second amplifier and the common output node.